Proteomic characteristics of six snake venoms from the Viperidae and Elapidae families in China and their relation to local tissue necrosis.

Patients envenomed by snakes from the Viperidae and Elapidae families in China often have varying degrees of local tissue necrosis. Due to the relative clinical characteristics of local tissue necrosis and ulceration following envenoming, this study has analyzed the proteome of six snake venoms from the Viperidae and Elapidae family, and the toxin profiles of each snake were compared and correlated with the clinical manifestations that follow cytotoxic envenoming. Deinagkistrodon acutus and Naja atra envenomation induce severe ulceration, which is absent in Bungarus multicinctus envenomation and mild in the other three vipers. It is interesting to note that the proportion of c-type lectins (CTL) (20.63%) in Deinagkistrodon acutus venom was relatively high, which differs from the venom of other vipers. In addition, three-fingered toxin (3FTx) (2.15%) is present in the venom of Deinagkistrodon acutus, but has not been detected in the remaining three vipers. Snake venom metalloprotease (SVMP) (34.4%-44.7%), phospholipase A2 (PLA2) (9.81%-40.83%), and snake venom serine protease (SVSP) (9.44%-16.2%) represent the most abundant families of toxin in Viperidae venom. The Elapidae venom proteome was mainly composed of neurotoxins and cytotoxins, including 3FTx (39.28%-60.08%) and PLA2 (8.24%-58.95%) toxins, however, the proportion of CRISPS (26.36%) in Naja atra venom was relatively higher compared to Bungarus multicinctus venom. Significant differences in SVMP, SVSP, and 3FTx expression levels exist between the Viperidae and the Elapidae family. The main toxins responsible for the development of tissue necrosis and ulcerations following Viperidae envenoming are hematotoxins (SVSMP, SVSP) and myotoxins (PLA2). Deinagkistrodon acutus venom contains high levels of CTL and traces of 3FTx, leading to more severe local necrosis. However, Naja atra venom can also cause severe local necrosis through the effects of myotoxin (3FTx, CRISP, PLA2). Bungarus multicinctus venom does not contain myotoxins, resulting in pure systemic neurological manifestations no obvious necrosis of local tissue in patients.

Immune-Related LncRNAs as Prognostic Factors for Pediatric Rhabdoid Tumor of the Kidney.

Background: Immune-related long noncoding RNAs (IrlncRNAs) are recognized as important prognostic factors in a variety of cancers, but thus far, their prognostic value in pediatric rhabdoid tumor of the kidney (pRTK) has not been reported. Here, we clarified the associations between IrlncRNAs and overall survival (OS) of pRTK patients and constructed a model to predict their prognosis. Methods: We accessed RNA sequencing data and corresponding clinical data of pRTK from the Therapeutically Applicable Research to Generate Effective Treatments (TARGET) database. An expression profile of immune-related genes (Irgenes) and lncRNAs of pRTK was extracted from the RNA sequencing data. IrlncRNAs were defined by co-expression analysis of lncRNAs and Irgenes. The limma R package was used to identify differential expression IrlncRNAs. Univariate and multivariate Cox regression analyses were conducted to build a prognostic IrlncRNAs model. The performance of this prognostic model was validated by multimethods, like ROC curve analysis. Results: A total of 1097 IrlncRNAs were defined. Univariate Cox regression analysis identified 7 IrlncRNAs (AC004791.2, AP003068.23, RP11-54O7.14, RP11-680F8.1, TBC1D3P1-DHX40P1, TUNAR, and XXbac-BPG308K3.5) and were significantly associated with OS. Multivariate regression analysis constructed the best prognostic model based on the expression of AC004791.2, AP003068.23, RP11-54O7.14, TBC1D3P1-DHX40P1, and TUNAR. According to the prognostic model, a risk score of each patient was calculated, and patients were divided into high-risk and low-risk groups accordingly. The survival time of low-risk patients was significantly better than high-risk patients (p < 0.001). Univariate (hazard ratio 1.098, 95% confidence interval 1.048-1.149, p value <0.001) and multivariate (hazard ratio 1.095, 95% confidence interval 1.043-1.150, p value <0.001) analyses confirmed that the prognostic model was reliable and independent in prediction of OS. Time-dependent ROC analysis showed that 1-year survival AUC of prognostic model, stage, age, and sex was 0.824, 0.673, 0.531, and 0.495, respectively, which suggested that the prognostic model was the best predictor of survival in pRTK patients. Conclusions: The prognostic model based on 5 IrlncRNAs was robust and could better predict the survival of pRTK than other clinical factors. Additionally, the mechanism of regulation and action of prognosis-associated lncRNAs could provide new avenues for basic research to explore the mechanism of tumor initiation and development in order to prevent and treat pRTK.

ebv-circRPMS1 promotes the progression of EBV-associated gastric carcinoma via Sam68-dependent activation of METTL3.

Epstein-Barr virus (EBV) is a tumor virus that is associated with a variety of neoplasms, including EBV-associated gastric carcinoma (EBVaGC). Recently, EBV was reported to generate various circular RNAs (circRNAs). CircRNAs are important regulators of tumorigenesis by modulating the malignant behaviors of tumor cells. However, to date, the functions of ebv-circRNAs in EBVaGC remain poorly understood. In the present study, we observed high ebv-circRPMS1 expression in EBVaGC and showed that ebv-circRPMS1 promoted the proliferation, migration, and invasion and inhibited the apoptosis of EBVaGC cells. In addition, METTL3 was upregulated in GC cells overexpressing ebv-circRPMS1. Mechanistically, ebv-circRPMS1 bound to Sam68 to facilitate its physical interaction with the METTL3 promotor, resulting in the transactivation of METTL3 and cancer progression. In clinical EBVaGC samples, ebv-circRPMS1 was associated with distant metastasis and a poor prognosis. Based on these findings, ebv-circRPMS1 contributed to EBVaGC progression by recruiting Sam68 to the METTL3 promoter to induce METTL3 expression. ebv-circRPMS1, Sam68, and METTL3 might serve as therapeutic targets for EBVaGC.

Comparative Transcriptome Provides a Systematic Perspective on Epstein-Barr Virus-Associated Gastric Carcinoma Cell Lines.

PURPOSE: Epstein-Barr virus (EBV) is widely recognised to cause various tumours, and EBV-associated gastric carcinoma (EBVaGC) is a special type of GC. It has obviously different clinical features and pathological manifestations from EBV-negative gastric carcinoma, but its progression remains elusive. The underlying cancer progression of viral infection detected by genome-wide transcriptome analysis has been demonstrated in numerous diseases. METHODS: We performed comparative RNA sequencing to identify gene expression signatures between GC and EBVaGC cell lines. The differentially expressed (DE) genes were analysed using gene ontology and pathway enrichment. RESULTS: A total of 4438 DE mRNAs, 3650 DE long non-coding RNAs (lncRNAs), and 248 DE circular RNAs (circRNAs) were detected in GC cells after EBV infection, most of which were highly related to oncogenesis. Likewise, EBV-coding RNA and non-coding RNA were also well-supplemented in EBVaGC. According to bioinformatics, DE mRNAs may contribute to the completion of EBV-infected host cells and modulate mitosis. Binding to actin and participating in adherens junctions to promote contact between the virus and cells are a potential function of DE lncRNAs. The roles of DE circRNAs were enriched in DNA repair and protein modification, and a typical example of this is acting as an miRNA sponge. The establishment of a circRNA-miRNA-mRNA network helps to determine the key elements in the progression of EBVaGC. CONCLUSION: This study is the first to systematically reveal the transcriptome landscape of EBVaGC, which will provide an essential resource for genomic, genetic, and molecular mechanisms in the future.

Investigation and Strategic Analysis of Family Barriers to Organ Donation in China.

BACKGROUND: Families play a prominent role in the eventual organ donation decision. Because the deceased cannot directly express their wishes, their families become the actual decision makers. In China, families are permitted to make decisions regarding organ donation that may not be in accordance with the wishes of the deceased family member, and objections by families are a main bottleneck in the donation process. METHODS: Face-to-face questioning was conducted with organ procurement organization coordinators. At the same time, questionnaires were distributed in 11 cities in Zhejiang Province. RESULTS: Of the respondents, 69.9% considered family consent necessary and 77.1% thought that the view of their family had a great, even decisive, influence on them to decide to become donors. If the deceased family member had registered as an organ donor, 65.2% of families decided that they would respect the wishes of the deceased person. Adult children (58.6%) were more likely to donate than parents (37.4%; χ2 = 123.009, P < .001). Those born after 2000 and after 1990 (62.5% and 52.8%, respectively) were much more likely to donate than those born after 1960 (18.1%; χ2 = 191.485, P < .001). The interviews indicated that there were high rates of donation refusals within potential donation families. Most donor families chose to make hidden donations, and the majority of donor families had a simple family structure. CONCLUSIONS: To promote organ donation, China needs to reconsider the role of families in the decision-making process. It is essential to increase organ donation awareness within the younger generation and encourage them to discuss with their families their willingness to donate.

Downregulated RPS-30 in Angiostrongylus cantonensis L5 plays a defensive role against damage due to oxidative stress.

BACKGROUND: Eosinophilic meningitis, caused by fifth-stage larvae of the nematode (roundworm) Angiostrongylus cantonensis, is mainly attributed to the contribution of eosinophils to tissue inflammatory responses in helminthic infections. Eosinophils are associated with the killing of helminths via peroxidative oxidation and hydrogen peroxide generated by the dismutation of superoxide produced during respiratory bursts. In contrast, when residing in the host with high level of eosinophils, helminthic worms have evolved to attenuate eosinophil-mediated tissue inflammatory responses for their survival in the hosts. In a previous study we demonstrated that the expression of the A. cantonensis RPS 30 gene (Acan-rps-30) was significantly downregulated in A. cantonensis L5 roundworms residing in cerebrospinal fluid with a high level of eosinophils. Acan-RPS-30 is a protein homologous to the human Fau protein that plays a pro-apoptotic regulatory role and may function in protecting worms from oxidative stress. METHODS: The isolation and structural characterization of Acan-RPS-30 were performed using rapid amplification of cDNA ends (RACE), genome walking and bioinformatics. Quantitative real-time-PCR and microinjection were used to detect the expression patterns of Acan-rps-30. Feeding RNA interference (RNAi) was used to knockdown the apoptosis gene ced-3. Microinjection was performed to construct transgenic worms. An oxidative stress assay was used to determine the functions of Acan-RPS-30. RESULTS: Our results showed that Acan-RPS-30 consisted of 130 amino acids. It was grouped into clade V with C. elegans in the phylogenetic analysis. It was expressed ubiquitously in worms and was downregulated in both L5 larvae and adult A. cantonensis. Worms expressing pCe-rps30::Acan-rps-30::rfp, with the refractile "button-like" apoptotic corpses, were susceptible to oxidative stress. Apoptosis genes ced-3 and ced-4 were both upregulated in the transgenic worms. The phenotype susceptible to oxidative stress could be converted with a ced-3 defective mutation and RNAi. rps-30-/- mutant worms were resistant to oxidative stress, with ced-3 and ced-4 both downregulated. The oxidative stress-resistant phenotype could be rescued and inhibited by through the expression of pCe-rps30::Acan-rps-30::rfp in rps-3-/- mutant worms. CONCLUSION: In C. elegans worms, downregulated RPS-30 plays a defensive role against damage due to oxidative stress, facilitating worm survival by regulating downregulated ced-3. This observation may indicate the mechanism by which A. cantonensis L5 worms, with downregulated Acan-RPS-30, survive in the central nervous system of humans from the immune response of eosinophils.

Epstein-Barr virus-derived circular RNA LMP2A induces stemness in EBV-associated gastric cancer.

Cancer stem cells (CSCs) are cancer-initiating cells that are not only a source of tumorigenesis but also the cause of tumour progression, metastasis and therapy resistance. EBV-associated gastric cancer (EBVaGC) is a distinct subtype of gastric cancer with unique clinicopathological and molecular features. However, whether CSCs exist in EBVaGC, and the tumorigenic mechanism of EBV, remains unclear. Here, NOD/SCID mice were injected subcutaneously with the EBVaGC cell line SNU719 and treated with 5-fluorouracil weekly. Successive generations of xenografts yielded a highly malignant EBVaGC cell line, SNU-4th, which displays properties of CSCs and mainly consists of CD44+ CD24- cells. In SNU-4th cells, an EBV-encoded circRNA, ebv-circLMP2A, expression increased and plays crucial roles in inducing and maintaining stemness phenotypes through targeting miR-3908/TRIM59/p53 axis. Additionally, high expression of ebv-circLMP2A is significantly associated with metastasis and poor prognosis in patients with EBVaGC. These findings not only provide evidence for the existence of CSCs in EBVaGC and elucidate the pathogenic mechanism of ebv-circLMP2A in EBVaGC, but also provide a promising therapeutic target for EBVaGC.

Comparison of Long-Term Outcomes and Sequelae Between Children and Adult Nasopharyngeal Carcinoma Treated With Intensity Modulated Radiation Therapy.

PURPOSE: Our purpose was to compare long-term survival outcomes and sequelae between child and adult nasopharyngeal carcinoma (NPC) in the era of intensity modulated radiation therapy. METHODS AND MATERIALS: Data on 285 patients with NPC aged ≤18 years at diagnosis and treated with intensity modulated radiation therapy between January 2004 and November 2016 were retrospectively reviewed. A propensity score matching method was adopted to screen matched adult patients with NPC at a ratio of 1:3. Survival outcomes and treatment-related toxicities between child and adult groups were compared. RESULTS: In total, 159 children and 477 adult patients with NPC were included in this study. The 5-year overall survival, distant metastasis-free survival, locoregional relapse-free survival, and disease-free survival between children and adults were 89.2% versus 83.6% (P = .144), 88.7% versus 83.5% (P = .124), 96.4% versus 89.1% (P = .013), and 86.5% versus 77.3% (P = .021), respectively. Subgroup analyses revealed that the young age was an independent prognostic factor of overall survival, distant metastasis-free survival, and locoregional relapse-free survival in the advanced N stage (N2-3) group and disease-free survival in the advanced T stage (T3-4) group and N2-3 and stage III-IVA groups. The most common sequela was ototoxicity (68.9%) in child patients and xerostomia (70.8%) in adult patients. Adult survivors had a significantly higher incidence of grade 3 to 4 late toxicities in xerostomia (17.6% vs 8.9%; P = .004), skin dystrophy (9.3% vs 3.7%; P = .022), neck fibrosis (8.3% vs 4.4%; P < .001), and radiation encephalopathy (0.8% vs 0; P = .006). Child survivors were more likely to develop grade 3 to 4 growth retardation and endocrine insufficiency (3.0% vs 0.3%; P = .014). CONCLUSIONS: Child patients with NPC achieved significantly better survival outcomes but fewer late toxicities than adult patients. However, we should pay great attention to growth problems of child survivors.

Improving pathological early diagnosis and differential biomarker value for hepatocellular carcinoma via RNAscope technology.

BACKGROUND: The diagnostic and prognostic values of glypican3 (GPC3) and glutamine synthetase (GS) proteins in hepatocellular carcinoma (HCC) have been reported, but their specificity and sensitivity remain low. Here, we applied RNAscope to improve HCC early pathological and differential diagnosis by estimating GPC3 and GS mRNAs. METHODS: We performed RNAscope and immunohistochemistry (IHC) to detect GPC3 and GS biomarkers on the tissue sections of 194 cases, including high- and low-grade liver dysplastic nodules; highly, moderately, and poorly differentiated HCCs; intrahepatic cholangiocarcinomas (ICCs); metastatic HCC; and carcinomas from other organs. RESULTS: The results showed that all the cases that were negative for GPC3 by RNAscope were also negative for this protein by IHC. The use of RNAscope assay improved the GPC3 and GS specificity and sensitivity by 20-30%. Hence, HCC shows early recognition and upgrades the metastatic HCC differentiation by 23% compared with IHC (p = 0.0001, 0.0064). Meanwhile, all liver cirrhosis, cholangiocytes and non-HCC samples were negative for GPC3 and GS except lymphocytes in lymphomas, and 2 (8.3%) out of the 24 ICC samples but not in the cancer cells. CONCLUSION: RNAscope for GPC3 and GS panel was highly specific and sensitive for the pathological identification of dysplastic nodules, early stages of HCCs, and would differentiate them from HCCs and metastatic tumors compared with IHC.

The roles of EBV-encoded microRNAs in EBV-associated tumors.

Epstein-Barr virus (EBV) is believed to be a pathogen causing a number of human cancers, but the pathogenic mechanisms remain unclear. An increasing number of studies have indicated that EBV-encoded microRNAs (EBV miRNAs) are expressed in a latency type- and tumor type-dependent manner, playing important roles in the development and progression of EBV-associated tumors. By targeting one or more genes of the virus and the host, EBV miRNAs are responsible for the deregulation of a variety of viral and host cell biological processes, including viral replication, latency maintenance, immune evasion, cell apoptosis and metabolism, and tumor proliferation and metastasis. In addition, some EBV miRNAs can be used as excellent diagnostic, prognostic and treatment efficacy predictive biomarkers for EBV-associated tumors. More importantly, EBV miRNA-targeting therapeutics have emerged and have been developing rapidly, which may open a new era in the treatment of EBV-associated tumors in the near future.

Identification of virus-encoded circular RNA.

Circular RNAs (circRNAs) are a novel class of non-coding RNA molecules in eukaryotic organisms that have potentially important roles in gene regulation. Nevertheless, whether viruses can encode circRNA is still uncertain. To examine whether large genome DNA viruses can generate circRNA during the infection of human cells, we performed RNA sequencing of ribosomal RNA-depleted total RNA from Epstein-Barr virus (EBV)-infected cell lines, including SNU-719, AGS-EBV, C666-1 and Akata. We identified an EBV-encoded circRNA, ebv_circ_RPMS1, that consists of the head-to-tail splicing of exons 2-4 from the RPMS1 gene. Furthermore, we demonstrated that ebv_circ_RPMS1 was localized in both cytoplasm and nuclei. Given that circRNAs shape gene expression by titrating microRNAs, regulating transcription and/or interfering with splicing, we identified a novel viral regulator of host and/or viral gene expression.

Brain metastasis in children with stage 4 neuroblastoma after multidisciplinary treatment.

INTRODUCTION: Brain metastasis is common in relapsed neuroblastoma patients, but the characteristics of brain metastasis remain largely unknown. This study aimed to investigate the status of brain metastasis with neuroblastoma in South China. METHODS: In this retrospective case-based study, 106 patients with stage 4 neuroblastoma from the Department of Pediatric Oncology in Sun Yat-sen University Cancer Center between January 2004 and May 2013 were included. The incidence, risk factors, and survival status of these patients were reviewed and analyzed. RESULTS: Of the 106 patients, 11 (10.4%) developed brain metastasis, accounting for 20.0% of 55 patients with relapse or progression. The age at initial diagnosis of the 11 patients ranged from 2 to 10 years (median 4 years), which was younger than that of the patients without brain metastasis (median 5 years, range 1-10 years, P=0.073). The male to female ratio of the 11 patients was 8:3, which was not significantly different from that of the patients without brain metastasis (P=0.86). Patients with brain metastasis had higher lactate dehydrogenase levels than those without brain metastasis, but the differences were not significant (P=0.076). Eight patients died, and 3 patients survived. The median interval from the initial diagnosis to the development of brain metastasis was 18 months (range 6-32 months). The median survival was 4 months (range 1 day to 29 months) after the diagnosis of brain metastasis. The median interval from the manifestation of brain metastasis to death was 3 months (range 1 day to 11 months). CONCLUSIONS: High-risk factors for brain metastasis in cases of neuroblastoma include bone marrow involvement and a younger age at initial diagnosis. Nevertheless, multiple treatment modalities can improve disease-free survival.

Inflammation scores predict survival for hepatitis B virus-related hepatocellular carcinoma patients after transarterial chemoembolization.

AIM: To compare the prognostic ability of inflammation scores for patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) undergoing transarterial chemoembolization (TACE). METHODS: Data of 224 consecutive patients who underwent TACE for unresectable HBV-related HCC from September 2009 to November 2011 were retrieved from a prospective database. The association of inflammation scores with clinicopathologic variables and overall survival (OS) were analyzed, and receiver operating characteristic curves were generated, and the area under the curve (AUC) was calculated to evaluate the discriminatory ability of each inflammation score and staging system, including tumor-node-metastasis, Barcelona Clinic Liver Cancer, and Cancer of the Liver Italian Program (CLIP) scores. RESULTS: The median follow-up period was 390 d, the one-, two-, and three-year OS were 38.4%, 18.3%, and 11.1%, respectively, and the median OS was 390 d. The Glasgow Prognostic Score (GPS), modifed GPS, neutrophil-lymphocyte ratio, and Prognostic Index were associated with OS. The GPS consistently had a higher AUC value at 6 mo (0.702), 12 mo (0.676), and 24 mo (0.687) in comparison with other inflammation scores. CLIP consistently had a higher AUC value at 6 mo (0.656), 12 mo (0.711), and 24 mo (0.721) in comparison with tumor-node-metastasis and Barcelona Clinic Liver Cancer staging systems. Multivariate analysis revealed that alanine aminotransferase, GPS, and CLIP were independent prognostic factors for OS. The combination of GPS and CLIP (AUC = 0.777) was superior to CLIP or GPS alone in prognostic ability for OS. CONCLUSION: The prognostic ability of GPS is superior to other inflammation scores for HCC patients undergoing TACE. Combining GPS and CLIP improved the prognostic power for OS.

Neuroprotective effect of Jatrorrhizine on hydrogen peroxide-induced cell injury and its potential mechanisms in PC12 cells.

The neuroprotective effects of Jatrorrhizine from Coptidis Rhizoma against hydrogen peroxide (H(2)O(2))-induced rat pheochromocytoma line PC12 injury and its potential mechanisms were evaluated in the present study. When cells were exposed to H(2)O(2) (200 µM) for 12h, there was a significant reduction in cell survival and activity of antioxidant enzyme (SOD and HO-1) and LDH release. In addition, increased ROS production, declined MMP and increased production of malondialdehyde (MDA) were observed. Preincubation of cells with Jatrorrhizine (0.01-10.0 µM) 24h prior to H(2)O(2) exposure markedly elevated cell viability and activities of antioxidant enzyme (SOD and HO-1), prevented LDH release and lipid peroxidation (MDA) production, attenuated the decrease of MMP and scavenged ROS formation. Jatrorrhizine also attenuated caspase-3 activation of the downstream cascade following ROS. Our results suggest that Jatrorrhizine holds potential for neuroprotective effects against H(2)O(2)-induced injury.

EFEMP1 expression promotes angiogenesis and accelerates the growth of cervical cancer in vivo.

OBJECTIVE: The study was to investigate the role of EFEMP1 in angiogenesis and growth of cervical carcinoma in vivo. METHODS: Effects of EFEMP1 on proliferation of Hela cells and HUVECs, invasion of Hela cells and migration of HUVECs, and adhesion of Hela cells to HUVECs were evaluated by MTT, Transwell chamber assay and adhesion assay, respectively. EFEMP1 overexpression in Hela cells was achieved by stable EFEMP1 gene transfection into Hela cells by Lipofectamin™ 2000 and the effectiveness of transfection was verified with western-blotting. The effect of EFEMP1 transfection upon the VEGF expression of Hela cells was detected with ELISA. The nude mouse models bearing cervical cancer were established with Hela cells transfected with EFEMP1 gene to observe the role of EFEMP1 in angiogenesis and growth of cervical cancer in vivo. VEGF expression and microvascular density of cervical cancer tissues were detected with immunohistochemistry and CD34 labeling respectively to elucidate the pathway by which EFEMP1 influences the growth of cervical cancer. RESULTS: Proliferation and invasion of Hela cells were promoted by the EFEMP1 protein. The EFEMP1 gene transfection into Hela cells was successful and EFEMP1 gene obtained stable high expression in Hela cells. Compared to the control, the tumors with EFEMP1 overexpression showed a faster growth rate and had a higher level of VEGF expression and microvascular density. EFEMP1 gene transfection elevated the VEGF protein level in Hela cells and EFEMP1 protein facilitated the adhesion of Hela cells to HUVECs. However, no direct effect of EFEMP1 was observed on proliferation, migration and tube formation of HUVECs. CONCLUSIONS: EFEMP1 promoted the angiogenesis and accelerated the growth of cervical carcinoma in vivo through a VEGF up-regulation pathway.

[Adsorption and sustained release of epirubicin from carbon-coated iron nanocrystals].

OBJECTIVE: To evaluate the adsorption and desorption of epirubicin (EADM) by carbon-coated iron nanocrystals (CCIN). METHODS: EADM standard curve was generated. After thorough mixture of CCIN and EADM with sonication, the mixture solution was centrifuged at high speed to obtain dissociated EADM for evaluating the adsorption capacity of CCIN. A dialyzer was used to evaluate the desorption of drug-loaded CCIN particles in different media (PBS, normal saline, or distilled water), at different temperatures, and with different quantities of loaded drug. RESULTS: The adsorption of EADM by CCIN presented linear adsorption before saturation and saturation adsorption, with an adsorption saturation point of about 160 microg/mg. The desorption of EADM from CCIN particles was affected by such factors as the extraction media, temperature, and quantity of the loaded drug. Compared to distilled water, PBS and normal saline improved the release rate of EADM from the drug-loaded CCIN particles. Higher temperature also contributed to higher release rate of EADM. Higher release rate of EADM occurred after the CCIN particles adsorbed greater amount of EADM. CONCLUSION: CCIN shows an EADM adsorption pattern of Langmuir isotherm adsorption. Such factors as higher temperature, PBS solution, higher speed of medium replacement, and more drug adsorbed all contribute to a higher release rate of EADM.

Structural analysis of fibroin heavy chain signal peptide of silkworm Bombyx mori.

To study the minimal length required for the secretion of recombinant proteins and silk proteins in posterior silk gland, the signal peptide (SP) of the fibroin heavy chain (FibH) of silkworm Bombyx mori was systematically shortened from the C-terminal. Its effect on the secretion of protein was observed using enhanced green fluorescent protein (EGFP) as a reporter. Secretion of EGFP fusion proteins was examined under fluorescence microscope. FibH SPs with lengths of 20, 18, 16 and 12 a.a. can direct the secretion of the reporter, yet those with lengths of 11, 10, 9, 8 and 1 a.a. can not. When the FibH SP was shortened to 12 a.a., the secretion efficiency was decreased slightly and cleavage occurred within EGFP. When 16 a.a. of the FibH SP were used, the secretion of fusion protein was normal and the cleavage site was between the Gly-Ser linker and Met, the starting amino acid of EGFP. These findings are applicable for the expression of foreign proteins in silkworm silk gland. The cleavage site of the SP is discussed and compared with the predictive results of the SignalP 3.0 online prediction program.

In vivo analysis of fibroin heavy chain signal peptide of silkworm Bombyx mori using recombinant baculovirus as vector.

In order to investigate the functional signal peptide of silkworm fibroin heavy chain (FibH) and the effect of N- and C-terminal parts of FibH on the secretion of FibH in vivo, N- and C-terminal segments of fibh gene were fused with enhanced green fluorescent protein (EGFP) gene. The fused gene was then introduced into silkworm larvae and expressed in silk gland using recombinant AcMNPV (Autographa californica multiple nuclear polyhedrosis virus) as vector. The fluorescence of EGFP was observed with fluorescence microscope. FibH-EGFP fusion proteins extracted from silk gland were analyzed by Western blot. Results showed that the two alpha helices within N-terminal 163 amino acid residues and the C-terminal 61 amino acid residues were not necessary for cleavage of signal peptide and secretion of the fusion protein into silk gland. Then the C-terminal 61 amino acid residues were substituted with a His-tag in the fusion protein to facilitate the purification. N-terminal sequencing of the purified protein showed that the signal cleavage site is between position 21 and 22 amino acid residues.

Loss of posterior silk gland transcription specificity of fibroin light chain promoter due to absence of 41 bp sequence containing possible inhibitor binding sites.

The gene encoding fibroin light chain protein (FibL) is specifically expressed in the posterior silk gland of silkworm and repressed in other tissues. The binding sites of several transcription factors involved in the silk gland transcription specificity of fibl promoter have been recognized, including SGFB, PSGF and BMFA. Here we report the leak expression of the enhanced green fluorescent protein (EGFP) reporter gene in tissues other than the posterior silk gland in vivo when under the control of a shortened fibl promoter with deletion of the 5' terminal 41 bp sequence, which is located at -650 nt to -610 nt upstream of the fibl transcription starting site. Assay of silk gland specificity of the promoters was performed by observation of green fluorescence in tissues of silkworm larvae following inter-haemocoelic injection of recombinant Autographa californica multiple nuclear polyhedrosis virus carrying the EGFP reporter gene controlled by different lengths of fibl promoters. Our results indicated that availability of the binding sites of several known factors, including SGFB, PSGF and BMFA, is not sufficient for intact silk gland transcription specificity of fibl promoter, and there are possible inhibitor binding sites in the 41 bp sequence (-650 nt to -610 nt) upstream of the transcription starting site which may be required to repress the activity of fibl promoter in other tissues.